Selective laser melting (SLM) or selective laser sintering (SLS) is a generative layer buildup method for processing powdered, in particular metallic and/or ceramic raw materials to form three-dimensional work pieces with complex shapes. To do so, a powdered raw material layer is applied to a carrier and exposed to laser radiation in the selective locations, depending on the desired geometry of the work piece to be created. The laser radiation penetrating into the powder layer causes heating and consequently melting or sintering of the powdered raw material particles. Then additional powdered raw material layers are applied successively to the layer that has already been laser-treated and the layer is irradiated again until the work piece has the desired shape and size. Selective laser melting or laser sintering may be used in particular for producing prototypes, tools, spare parts or medical prostheses, for example, dental or orthopedic prostheses by means of CAD data.
An SLM/SLS strategy consists of virtually dividing the work piece to be produced into a shell region and a core region. In producing the work piece, the shell region is then irradiated first with a beam of light having a comparatively narrow and/or Gaussian beam profile, whereas then the core region is subsequently irradiated with a beam of light having a comparatively broad and/or homogeneous beam profile. At least two different beam profiles are thus necessary for this so-called core-shell strategy.